(a) Field of the Invention
The present invention relates to a process for the production of solvent-refined coal useful as a starting material for other carbonaceous products. More particularly, the present invention relates to a process for the elective production of a starting material for micromosaic carbonaceous products, coarse mosaic carbonaceous products or needle like carbonaceous products, wherein the starting coal in a solvent is heated under hydrogen pressure for a period of time selected according to the oxygen/carbon (O/C) ratio of the starting coal used and of the product desired.
(b) Description of the Prior Art
In the prior art processes for the production of carbonaceous products, the structure and properties of the resultant carbonaceous products and materials are determined almost exclusively from those of the starting materials. For example, a heavy oil of the petroleum series is used as a starting material for needle like carbonaceous products, while several types of coal are combined into a single starting material for blast furnace coke. In recent years, however, not only did the price of many starting materials increase considerably, but also the quality thereof became noticeably lower, so that supply of acceptable starting carbonaceous materials has been increasingly difficult. Thus, there is a great demand for a process for producing the desired carbonaceous products from easily available starting materials. In particular, there is a great demand for developing a process for the production of micromosaic carbonaceous products, coarse mosaic carbonaceous products and needle like carbonaceous product from coal varieties which are readily available and plentiful, especially brown coal, lignite and the like.
In general, these coals are only slightly susceptible of graphitization. It is known, however, that the degree of coal graphitization can be improved by converting them into solvent-refined coals by hydrogenolyzing the starting coal in a solvent, removing insoluble matters therefrom and then removing the solvent. To obtain the desired carbonaceous products according to the known processes, it is necessary to specify the composition of the solvent-refined coal utilizable as a starting material for the carbonaceous product. Thus, it is a key problem (for obtaining the specific solvent-refined coal) to select the exact composition of the starting coal and the proper hydrogenolysis parameters.